Cell hybridisation between genera which are only distantly related to each
other leads to the formation of hybrid cell lines. After somatic cell
fusion between soya and tobacco, Kao (1977) selected cell lines in which
the presence of tobacco characters could be proved using cytological and
isoenzymatic analyses even after several years, despite the fact that the
chromosomes were lost. Cell lines of this type have also been produced for
other genera.

This may be compared to the Phragmipaphium, a hybrid of Paphiopedilum x
Phragmipedium, which seems to be a definite intergeneric hybrid, though the
chromosomes appear to be entirely maternal.